1. Field of the Invention
The invention relates in general to an inverter unit, and more particularly to an inverter unit using an open lamp lock circuit to determine whether to output a voltage to light up a lamp of a liquid crystal display panel.
2. Description of the Related Art
Before a liquid crystal display panel module leaves the factory, an inverter is used to light up the backlight source and the lamp of the liquid crystal display panel module is tested, such that defective products are detected and product quality is assured. However, as the display panel modules have various sizes and are incorporated with different number of lamps, inverters are used in large amount and large variety as indicated in FIGS. 1A and 1B. FIG. 1A shows a lamp of a display panel module is lit up by a conventional inverter with single-end output. FIG. 1B shows a lamp of a display panel module is lit up by a conventional inverter with dual-end output. The inverter 120 includes an inverter unit 121, and is used to output an output voltage to light up the lamp 111. The inverter 120 is only applicable to the display panel module 110 having only one lamp 111. When the two lamps 131 and 132 of the display panel module 130 are to be lit up, the inverter 140 is used. The inverter 140 has two inverter units 141 and 142, and is used to output two output voltages to light up the lamps 131 and 132, respectively.
When inspecting the display panel module having various sizes or different number of lamps, the inverter is exclusive to a particular display panel module, not only increasing the manufacturing cost of the inverter and the testing cost of the display panel module, but also adding inconvenience to the inspector for having to replace various types of inverters, reducing testing efficiency, and exposing the inspector to the risk of electric shock during inspection.
Therefore, how to develop an inverter which can be easily and safely applied to the display panel module having various sizes or different number of lamps has become an imminent issue to be resolved.